1. Field of the Invention
The present invention relates to a guidance system for pull-type equipment, and more specifically, to a guidance system capable of adjusting the angle of a vehicle drawbar in connection with an implement as it is pulled across a surface. Furthermore, the guidance system allows an equipment operator an ability to alter the towing path of the implement while on-the-fly to account for gravitational forces acting laterally on the implement as it is towed across a surface having a non-horizontal grade or as may be necessary to avoid obstacles and the like.
2. Background of the Prior Art
Typical pull-type equipment is arranged in a manner such that a towing vehicle provides locomotion to a trailing implement provided to perform various functions. Agricultural pull-type equipment is designed to perform various functions on a field in which crops are planted, grown, and harvested, while other pull-type equipment is designed to perform other functions, such as grading a surface of snow or earth. In the case of agricultural pull-type equipment, it is highly desirable to work the soil or apply chemicals by maneuvering the equipment between rows of crops without disrupting the crops themselves. Row crops grown in fields with a generally flat grade pose little challenge to an operator once the equipment has been properly aligned such that the equipment provides its desired function without disturbing the crops. However, maintaining proper alignment of equipment as it travels through rows of crops becomes increasingly difficult in a field with a non-horizontal grade, such as a hillside, due to the forces of gravity acting on the equipment in a manner such that the trailing elements of the implement in-tow move laterally relative to the forward motion of the implement.
In the case of other pull-type equipment, it is highly desirable to manipulate the path of the implement in addition to that provided through steering the towing vehicle. Not withstanding instances where correction for gravity is the primary consideration, in other circumstances, it is desirable for an equipment operator to manipulate the path of the implement in-tow independent from the towing vehicle. Examples illustrating such circumstances include maneuvering the implement through a gate or opening, maneuvering over or under a viaduct or bridge, and manipulating the relative position of equipment during vehicle-implement connection, disconnection, and storage.
Attachment of an implement to a towing vehicle is commonly accomplished by providing an elongated neck portion of an implement for marriage to a drawbar located at the rear of a towing vehicle. The elongated neck allows the towing vehicle to change directions without interfering or coming into contact with the implement in-tow at a point other than the pivot point at which the vehicle drawbar is connected to the implement.
It is known in the art to provide adjustable drawbars capable of vertical height alteration. It is also known to provide drawbars extended to the rear of a vehicle capable of altering the fixed angular position of the drawbar.
Nevertheless there remains a longstanding need for improvements in adjustable drawbar assemblies. Such improvements result in guidance systems for pull-type equipment which will allow an equipment operator an ability to adjust the offset of the drawbar at an angle while underway. Typically, adjustments are necessary to correct the tendency of a towed implement to slide laterally down a grade when the equipment is moving in a forward direction. Further improvements would provide automatic corrective feedback mechanisms whereby a control module would sense a change in grade and relay a command to the drawbar assembly to correct the tendency of the towed implement to slide laterally down a grade when the equipment is moving in a forward direction. Improvements further still would allow an equipment operator an ability to manually maneuver the towed implement to avoid impact with an object in or near the path of the towed implement or to generally improve operator ability to manipulate the position of the towed implement. Further improvements would provide automatic corrective feedback mechanisms whereby a control module would sense the alignment of crop rows and relay a command to the drawbar assembly to maintain implement alignment with the crop rows. Improvements further still would provide a variety of drawbar signaling and feedback options, including, but not limited to, mechanically-derived input signaling, pendulum-derived input signally, mechanically-derived feedback signaling, ultrasonic-, ultraviolet-, and laser-derived feedback signaling.
An improved equipment guidance system and assembly is described comprising a drawbar in communication with a drawbar signaling means and in further communication with a drawbar feedback means such that the drawbar is adjustable left or right of center depending on towing vehicle-implement operating conditions and a comparison of the drawbar signal and the feedback signal. According to one aspect of the present invention, the improved guidance system and assembly is an integrated component of the drawbar a towing vehicle. According to another aspect of the present invention, the improved guidance system and assembly comprises a top plate in releasable engagement with a drawbar of a towing vehicle, a supplemental or ancillary drawbar pivotable about a forward location and movable to an offset position left or right of center by a pair of pistons, and a bottom plate for attachment to the ancillary drawbar and the top plate. The pistons are controlled by a control box that dictates in concert the extension and retraction of the left and right pistons. A signal from the control box is generated from a plurality of sources.
One example of a signal source is a tilt sensor that measures inclination relative to gravity. The response of the tilt sensor depends on the magnitude of gravity parallel to the sensor element. The output of the tilt sensor is automatically and constantly conveyed to the control box where a command is sent to electro-hydraulic valves that control the extension and retraction of the left and right pistons to correct for the measured tilt. Another example of a signal source is an automatic crop sensing wand system wherein flexible wires or xe2x80x9cwhiskersxe2x80x9d are used to physically sense the row of crops to provide steering signal that is used to direct the towing vehicle between the rows. Whiskers monitor tractor alignment with row crops through a plurality of sensors the output of which is automatically and constantly conveyed to the control box where a command is sent to electro-hydraulic valves that control the extension and retraction of the left and right pistons to correct for the measured disparity measured by the whiskers. Other examples of signal sources include mechanically-derived input signaling and pendulum-derived input signaling. Yet another example of a signal source can be generated manually from an operator of the towing vehicle. The operator can direct the drawbar left or right by activating a handheld or mounted switch that signals the control box command to send a signal to the electro-hydraulic valves that extend and retract the left and right pistons to manipulate the position of the drawbar accordingly.
According to another aspect of the invention, drawbar feedback means comprises a smart cylinder in electronic feedback communication with the control box. Yet another aspect of the invention comprises a mechanically-derived signal as a feedback means, such as a lever or touch-sensitive wire. Other aspects of the drawbar feedback means comprise photoelectric, ultrasonic-, ultraviolet-, and laser-derived feedback signaling.
According to yet another aspect of the invention, there is provided an equipment guidance system on a towing vehicle for towing an implement comprising:
a drawbar pivotable about a forward location and movable to an offset position left or right of center;
a means for said ancillary drawbar adjustment;
a signaling means for directing ancillary drawbar adjustment;
said ancillary drawbar pivotable to an offset position between a substantially center position and a plurality of positions left of center; and
said ancillary drawbar pivotable to an offset position between a substantially center position and a plurality of positions right of center.
According to another aspect of the invention, there is provided for attachment to a drawbar of a towing vehicle an equipment guidance system for towing an implement comprising:
a top plate for releasable engagement of vehicle drawbar;
an ancillary drawbar pivotable about a forward location and movable to an offset position left or right of center;
a means for said ancillary drawbar adjustment;
a signaling means for directing ancillary drawbar adjustment;
a bottom plate for supporting said ancillary drawbar and said top plate;
said ancillary drawbar pivotable to an offset position between a substantially center position and a plurality of positions left of center; and
said ancillary drawbar pivotable to an offset position between a substantially center position and a plurality of positions right of center.
Preferably, said means for the ancillary drawbar adjustment comprises a pair of hydraulic cylinders in receptive engagement with the ancillary bar, wherein a first end of each cylinder is attached to said top plate at a position proximal to a forward portion of the assembly on either side of the ancillary bar, and wherein a second end of each cylinder is further attached to said ancillary bar at a position distal to a forward portion of the assembly on either side of the ancillary bar.
According to a another aspect of the invention, there is provided for attachment to a drawbar of a towing vehicle an equipment guidance system for towing an implement comprising:
a top plate for releasable engagement of vehicle drawbar;
an ancillary drawbar pivotable about a forward location and movable to an offset position left or right of center;
a means for said ancillary drawbar adjustment;
a signaling means for directing ancillary drawbar adjustment;
a bottom plate for supporting said ancillary drawbar and said top plate;
said ancillary drawbar pivotable to an offset position between a substantially center position and a plurality of positions left of center; and
said ancillary drawbar pivotable to an offset position between a substantially center position and a plurality of positions right of center.
said means for the ancillary drawbar adjustment comprises a pair of hydraulic cylinders in receptive engagement with the ancillary bar, wherein a first end of each cylinder is attached to the top plate at a position proximal to a forward portion of the assembly on either side of the ancillary bar, and wherein a second end of the cylinder is further attached to the ancillary bar at a position distal to a forward portion of the assembly on either side of the ancillary bar; and
a means for automatically adjusting said offset position according to a signal source in communication with a drawbar feedback signal.
Preferably, said means for automatically adjusting the offset position according to the grade of the ground on which the implement is being towed comprises a measuring means for measuring the grade level of said ground, wherein said measuring means is in communication with a control means for controlling said hydraulic cylinders acting in concert to adjust the offset of the ancillary drawbar rightward or leftward to adjust the on-the-fly orientation of the implement in-tow.